Several surgical clips are known in the art. Applied Medical distributes a surgical clip called EPIX Universal CA500 which has the two substantially straight clip arms connected to each other via a substantially V-shaped portion. The two straight clip arms run essentially in parallel to the longitudinal axis of the surgical clip, and relatively small bending radii are formed in the transient regions between the clip arms and the connection portion as well as at the throat of the connection portion. This means that the transient regions are formed by breaks. Comparable surgical clips with comparable geometry are distributed also by United States Surgical, labeled Endo Clip Autosuture 5 mm, and by Ethicon, labeled Ligamax 5.
The Endo Clip Autosuture III 5 mm, which is distributed by Unites States Surgical as well, has a somewhat different geometry. This clip also comprises two substantially straight and parallel clip arms, and a connection portion for the two straight clip arms which is formed with a throat having a smallish radius of curvature. In contrast to the previously described surgical clips, the transient regions between the clip arms and the connection portion are formed with a distinctly larger radius of curvature, and thus rather as bent portions than as broken portions.
A patent application U.S. 2011/0224701 A1 discloses a surgical clip having a semicircular outer surface and a profiled inner surface. The semicircular outer surface serves to prevent blocking of the clip in the jaw part of the clip applicator, and the profiled inner surface is to improve the grip on the clamped tissue. In a side view, the clip arms of the clip respectively have straight portions which run parallel to each other in the region of the distal end of the clip, i.e. at its open side. Besides, the clip arms consist of plural and substantially indeformable sections which are interconnected by deformable sections.
All known clips have in common that each clip arm has a substantially straight portion, and that the connection portion has two substantially straight portions. Then, more or less curved portions are formed in the throat and in the transient region between the clip arm and the connection portion. Besides, all of these clips are single rack clips, i.e. clips that can be bent from a piece of wire and substantially extend in a plane (aside from the wire bead).
A problem with this kind of clips resides in that they exhibit unfavorable performance upon application, i.e. upon pressing or compressing by means of a clip applicator. On the one hand, due to the formation of the smallish radius of curvature in the transient region from the clip arm to the connection portion, a region is created in which the material of the clip (a metal such as titanium or titanium alloys) is stretched more than in the adjacent regions which, resulting in that this region, which is in the following referred to as a break, cannot completely be deformed back into a straight form upon compressing the clip with an applicator. Thus, a spot remains in the compressed clip at which the two clip arms are spaced farther away from each other. This leads to a suboptimal closure of the respectively clipped, i.e. pinched, vessel.
A further problem of this kind of clips resides in that the barring of these clips in the compressed state is weak at the distal ends of the clip arms. This means that a force that leads to a barring of the vessel is barely applied onto the vessel at the distal clip ends. During the compression process the two parallel clip arms are deformed inwardly around the throat of the clips. Thereby, only the break and the transient region, respectively, of the clip remain in contact with the respective limb of the clip applicator. The break between the clip arm and the connection portion is bent open only when the distal ends of the clips touch each other (if no tissue is seized) or become on both sides applied to the tissue to be seized (if tissue is seized). Thereby, the distal ends of the clip arms deform to the outside, and the relevant force transmission point into the tissue relocates toward the break. This in turn relieves the distal ends of the clip arms, and they relieve their elastic deformation (substantially while maintaining their current position). Now, if the break in the clip arm has been deformed back as far as possible, i.e. the clip is completely compressed, this results in that the clip can hardly muster any further barring force and compression force, respectively, because the distal ends are easily and elastically deformable to the outside and because there are locations in the middle portion of the clip where the clip arms touch each other (if no tissue is seized) or the clip arms apply on both sides of the seized tissue substantially punctiformly (in the following, this region will be referred to as a middle contact region in both cases). Namely, in this manner, the distal ends have been completely relieved toward the end of the compression process, when the break in the clip arm has been deformed back with a force by far exceeding the force being required to bring the remaining regions of the clip into the compressed form of the clip. The compression force, which should technically be distributed as uniformly as possible over the length of the compressed clip, then concentrates on the vicinity of the clip throat and the middle contact region of the clip.
It is an object of the invention to provide a surgical clip in which a uniform and as small as possible gap forms between the clip arms, and in which the clip arms deliver a sufficient compression force to the point of their distal end. A further object of the invention resides in providing a surgical clip which exercises a uniform force onto the seized tissue over substantially the entire clip length. A still further object of the invention is to provide a manufacturing method for such a clip.
Definition of Terms
A clip has a non-compressed initial state and a compressed final state. Normally, tissue is located in the compressed state between two mating clip arms, such as a hollow organ like a blood vessel. In this case, the thickness and the consistency of the blood vessel wall determine the width of the gap between the clip arms in the compressed state. For this reason, specifications of the gap thickness of the clip in the compressed state herein always refer to the case that no tissue is located between the clip arms, because only then a meaningful comparison with the clips known from the art is possible. For this purpose, it can be set forth that the quality of a gap of the clip in the compressed state without any tissue located in-between give a clear indication toward the quality of the gap with tissue located in-between. The quality of the gap is also determined by the gap width and by the compression force applied by the clip arms along the clip arms. For example, if in a clip, without any tissue laying in-between, a parallel gap is formed which has a substantially equal compression force over its substantially entire length, a substantially equal compression force over the substantially entire length of the tissue-clip-contact line/area would result in the same clip with tissue laying in-between.
A clip consists of an even number of clip arms, of which respective two are associated with each other and form a plane. In this manner, plural substantially parallel planes are formed in case of plural clip arm pairs. The clip plane is a plane which runs in parallel to the planes described above and which substantially bisects the clip in the direction perpendicular to this plane. In each case, a pair of mating clip arms is connected at its proximal ends and forms a clip throat in the connection portion. The longitudinal axis of a clip or a pair of clip arms is a line extending from the clip throat to the middle between the two distal ends of the respective clip arms. This longitudinal axis (chain dotted line) runs proximally-distally.
The clip length L is the distance from the outside of the clip throat to the vertical projection of the distal ends of the clip arms onto the longitudinal axis of the clip, the clip width B is the distance of the outsides of the distal ends of two mating clip arms (i.e. these two clip arms form together a pair of clip arms), and the clip height H is the extension of the clip in a direction perpendicular to the clip plane. The clip length L, the clip width B and the clip height H refer to the outer dimensions of the respective clip.
The clear, or usable, clip length L1 is the distance from the inside of the clip throat to the vertical projection of the distal ends of the clip arms onto the longitudinal axis of the clip, the clear, or usable, clip width B1 is the distance of the inner sides of the distal ends of two mating clip arms (i.e. these two clip arms form together a pair of clip arms), and the clear, or usable, clip height H1 is the distance of two adjacent clip arms, which together do not form a pair of mating clip arms. The clear clip length L1, the clear clip width B1 and the clip height H1 refer to the inner dimensions of the respective clip.
The clip arm length l is the length of the unwinding of one clip arm into a line, wherein the clip arm length l refers to the neutral fiber (dashed line) of the clip arm. The neutral fiber is the geometric location of the centers of the moments of inertia along the respective clip arm. The length on the clip arm la is indicated in percent (%), wherein a length on the clip arm of 0% corresponds to the clip throat, i.e. the location where the neutral fiber of the clip arm and two mating clip arms, respectively, intersect the longitudinal axis of the clip, and a length on the clip arm of 100% corresponds to the distal end of the respective clip arm. In a ring clip made of a sheet metal, the clip arm width b corresponds to the distance of the side edges of a clip arm. In a ring clip made of a sheet metal, the clip arm height h corresponds to the thickness of the sheet metal. When the clip arm width and/or the clip arm height is/are variable over the clip arms, various and variable clip arm widths and heights b′, b″, h′ may be present. The tangent angle α is the angle a tangent to the neutral fiber of the respective clip takes with a line standing vertically on the longitudinal axis of the clip. The tangent angle α is, thus, always between 0° and substantially 90°. In the following and unless stated otherwise, the description of the clip refers to the uncompressed state of the clip, in which the same is strainless.
On the one hand, the term of the surgical tubular shaft instrument comprises in this application endoscopic instruments, such as endoscopic clip applicators. On the other hand, this term also comprises surgical instruments for an open operation in which the functional portion and the effective portion, respectively, of the instrument is separated from the actuation portion and the handle portion, respectively, by a shaft or a shaft-like component. Here, the term shaft and shaft-like component, respectively, designates a component whose dimensions and location vis-à-vis the actuation portion (e.g. a handle) are substantially invariable during an actuation of the surgical instrument. An axial displacement along the axis of the shaft or shaft-like component and a torsion across or around this axis is thereby allowable, however a substantial displacement vis-à-vis this axis such that the two ends of the component substantially depart from this axis is not allowable. Preferably, the length of a shaft or shaft-like component is larger than the two other dimensions (width, depth) thereof, and further preferably, it is formed in a slim manner. Thereby, the shaft and the shaft-like component, respectively, need not to be round, closed, tubular or thin walled. It is decisive here that it is about an instrument which, unlike ordinary scissors, does not have a pivotal point around which all essential constituents of the instrument turn, but in which the force to open and close the jaw part is transferred via a relative axial movement of a component vis-à-vis the shaft.
In this application, the functional portion and the effective portion, respectively, is the region of the surgical tubular shaft instrument in which the actual function thereof is carried out. In a needle holder, it is the region seizing and holding the needle, i.e. the distal regions of the limbs. In scissors, it is the region that cuts the tissue or something other, i.e. the region at which the two shearing edges that glide past each other are formed. In a clip applicator, it is the region in which the clip is initially held while it is brought to the proper location and in the proper position by the surgeon, and in which the clip is subsequently administered, i.e. compressed. In other instruments, the definition of the functional portion and the effective portion, respectively, is to be applied correspondingly.
The effective range is the region of a singular limb in which the limb effects the intended function of the instrument, i.e. a gripping area in a needle holder, a shearing edge in scissors, and an application region of the clip.
Here, a closing and a closing operation, respectively, of the jaw part means that the effective ranges of the limbs typically move toward each other during the closing operation. In the case of scissors, the effective ranges of the limbs, i.e. the shearing edges, move past each other, and thereby apart from each other again, during the later course of the closing operation. This entire process is nevertheless referred to as a closing operation of the jaw part. In general terms, a closing operation designates the performance of the function assigned to the instrument, such as a seizing of tissue or for example a needle, a cutting of tissue or other matter, an administration of a clip or a spreading of tissue or other objects such as a clip. A subsequent opening and a subsequent opening operation, respectively, then designates the return of the limbs and, thus, also of the effective ranges and the distal regions, respectively, of the limbs of the jaw part of the respective instrument, to their initial position. In a surgical spreader, the assignment is just opposite because it performs its task when the limbs substantially move away from each other, i.e. carry out an opening operation, whereas a returning of the limbs to the initial position corresponds to a closing operation. Nevertheless, also in such an instrument there is a clear opening operation and a clear closing operation.